From a95c229e12496194b513e3623ab44f9530f272ba Mon Sep 17 00:00:00 2001 From: Clifford Wolf Date: Sat, 17 Jan 2015 13:56:53 +0100 Subject: [PATCH] Fixed a bug in opt_muxtree for "mux forests" --- passes/opt/opt_muxtree.cc | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/passes/opt/opt_muxtree.cc b/passes/opt/opt_muxtree.cc index fa91d4537..33dd12a03 100644 --- a/passes/opt/opt_muxtree.cc +++ b/passes/opt/opt_muxtree.cc @@ -69,6 +69,8 @@ struct OptMuxtreeWorker std::vector mux2info; + std::set root_muxes; + OptMuxtreeWorker(RTLIL::Design *design, RTLIL::Module *module) : design(design), module(module), assign_map(module), removed_count(0) { @@ -159,15 +161,26 @@ struct OptMuxtreeWorker log(" Evaluating internal representation of mux trees.\n"); - std::set root_muxes; + dict> mux_to_users; + for (auto &bi : bit2info) { + for (int i : bi.mux_drivers) + for (int j : bi.mux_users) + mux_to_users[i].insert(j); if (!bi.seen_non_mux) continue; for (int mux_idx : bi.mux_drivers) root_muxes.insert(mux_idx); } - for (int mux_idx : root_muxes) + + for (auto &it : mux_to_users) + if (GetSize(it.second) > 1) + root_muxes.insert(it.first); + + for (int mux_idx : root_muxes) { + log(" Root of a mux tree: %s\n", log_id(mux2info[mux_idx].cell)); eval_root_mux(mux_idx); + } log(" Analyzing evaluation results.\n"); @@ -317,7 +330,8 @@ struct OptMuxtreeWorker parent_muxes.push_back(m); } for (int m : parent_muxes) - eval_mux(knowledge, m); + if (!root_muxes.count(m)) + eval_mux(knowledge, m); for (int m : parent_muxes) knowledge.visited_muxes.erase(m); @@ -355,7 +369,7 @@ struct OptMuxtreeWorker } if (did_something) { - log(" Replacing known input bits on port %s of cell %s: %s -> %s\n", log_id(portname), + log(" Replacing known input bits on port %s of cell %s: %s -> %s\n", log_id(portname), log_id(muxinfo.cell), log_signal(muxinfo.cell->getPort(portname)), log_signal(sig)); muxinfo.cell->setPort(portname, sig); } -- 2.30.2